Cathode materials having high energy density and lithium secondary battery containing the same

a lithium secondary battery and cathode material technology, applied in the direction of non-metal conductors, cell components, oxide conductors, etc., can solve the problems of disadvantage, low energy density, and low energy density of lithium secondary batteries, so as to improve the mobility of lithium ions and rate properties, reduce the amount of transition metals present, and stabilize the crystal structure of cathode materials

Active Publication Date: 2012-09-06
LG ENERGY SOLUTION LTD
View PDF2 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0055]Such a lithium nickel-manganese-cobalt oxide maintains an average oxidation number of transition metals at a level larger than +3, thus considerably decreasing the amount of transition metals present in the reversible lithium layer based on the stable crystal structure of the cathode material and improving mobility of lithium ions and rate properties as well as capacity.
[0056]Regarding the aspect (i), the oxide powder (b2) has an average oxidation number of transition metals except lithium, higher than +3, thus decreasing an average size of transition metal ions, increasing the size difference between lithium ions, and promoting separation between layers, thereby forming a stable layered crystal structure.

Problems solved by technology

LiCoO2 has several disadvantages of being relatively expensive, having low charge / discharge capacity of about 150 mAh / g and unstable crystal structure at a voltage of 4.3 V or higher and the risk of reacting with an electrolyte to cause combustion.
Furthermore, LiCoO2 is disadvantageous in that it undergoes great variation in physical properties depending upon variation in parameters in the preparation process thereof.
Secondary batteries comprising such a cathode material exhibit low stability at high electric potential or have a limitation of application to mass-production.
Use of secondary batteries is expected to further increase and the above problems and problems associated with stability of batteries and high-temperature storage properties at high electric potentials arise.
However, conventional mixture-type cathode materials have a limitation of the difficulty of obtaining superior synergetic effects to the case of simple combination of two ingredients.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Cathode materials having high energy density and lithium secondary battery containing the same
  • Cathode materials having high energy density and lithium secondary battery containing the same
  • Cathode materials having high energy density and lithium secondary battery containing the same

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0109]LiCoO2 having a monolithic structure and D50 of about 15 to about 20 μm and LiNi0.53Co0.2Mn0.27O2 having D50 of about 5 to 8 μm, as an agglomerate of micro particles a size of about 1 to about 2 μm obtained in Preparation Example 1-1 were mixed at a ratio of 50:50 to prepare a cathode material mix.

[0110]The cathode material mix, Super P as a conductive material and polyvinylidene fluoride as a binder were mixed at a weight ratio 92:4:4, and N-methyl pyrrolidone (NMP) was added thereto to prepare a slurry. The cathode slurry was applied to an aluminum collector, followed by drying in a vacuum oven at 120° C. to produce a cathode.

[0111]In addition, mesocarbon microbead (MCMB) as an anode active material, super P as a conductive material and PVdF as a binder were mixed at a weight ratio of 92:2:6, followed by dispersion in NMP and coating on a copper foil, to produce an anode.

[0112]A porous membrane made of polypropylene was inserted between the anode and cathode thus obtained to...

example 2

[0113]A cathode material mix was prepared and a lithium secondary battery was produced in the same manner as in Example 1 except that a weight ratio of LiCoO2 and LiNi0.53Co0.2Mn0.27O2 in the cathode material mix was 70:30.

experimental example 1

[0116]Discharge capacity (1C rate charge) of batteries produced in Examples 1 and 2 and the battery produced in Comparative Example 1 were measured at 0.2C, 0.5 C, 1C, 1.5C and 2C rate and a ratio of discharge capacity at each C-rate with respect to 5C rate capacity was calculated. The results thus obtained are shown in FIG. 3.

[0117]As can be seen from FIG. 3, discharge capacity of the battery of Comparative Example 2 rapidly decreases, as C-rate increases, and on the other hand, batteries of Examples 1 and 2 of the present invention exhibited considerably superior C-rate properties, and in particular, the battery of Example 2 containing 30% of oxide (b) exhibited superior C-rate properties in which discharge capacity is as high as 90% or more at a 2C rate. In addition, it can be seen that this improvement in C-rate properties was exhibited even at a low C-rate of 1C, and batteries of Examples 1 and 2 exhibited more considerable improvement in discharge properties, as C-rate thereof...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
sizeaaaaaaaaaa
molar ratioaaaaaaaaaa
total weightaaaaaaaaaa
Login to view more

Abstract

Disclosed is a cathode material comprising a mixture of an oxide powder (a) defined herein and an oxide powder (b) selected from the group consisting of an oxide powder (b1) defined herein and an oxide powder (b2) defined herein and a combination thereof wherein a mix ratio of the two oxide powders (oxide powder (a): oxide powder (b)) is 50:50 to 90:10. The cathode material uses a combination of an oxide powder (a) and 50% or less of an oxide powder (b) which can exert high capacity, high cycle stability, superior storage stability and high-temperature stability, thus advantageously exhibiting high energy density and realizing high capacity batteries.

Description

TECHNICAL FIELD [0001]The present invention relates to a cathode material with a high energy density and a lithium secondary battery comprising the same. More specifically, the present invention relates to a cathode material comprising a mixture of an oxide powder (a) having a specific composition and an oxide powder (b) having a specific composition, wherein a mix ratio of the two oxide powders (oxide powder (a): oxide powder (b)) is 50:50 to 90:10.BACKGROUND ART [0002]In recent years, chargeable and dischargeable secondary batteries are widely used as energy sources of wireless mobile equipment. Of these, lithium secondary batteries are generally used due to advantages such as high energy density, discharge voltage and power stability.[0003]Lithium secondary batteries use metal oxide such as LiCoO2 as a cathode material and carbon as an anode material and are fabricated by inserting a polyolefin-based porous membrane between an anode and a cathode and swelling a non-aqueous electr...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(United States)
IPC IPC(8): H01M2/18H01B1/08H01M50/417H01M50/426H01M50/431
CPCH01M2/1653H01M2/166H01M4/131H01M4/525H01M2/1673Y02T10/7011H01M10/052H01M2/1633H01M2/0287Y02E60/122H01M4/364H01M4/622H01M4/505H01M2/1646H01M2004/028H01M4/623Y02E60/10H01M50/124H01M50/446H01M50/431H01M50/46H01M50/417H01M50/426Y02T10/70
Inventor CHOI, SEUNGEUNGOH, EUNYOUNGLEE, HYANG MOKKANG, HEEGYOUNGRYU, SANGBAEKKIM, KIWOONG
Owner LG ENERGY SOLUTION LTD
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap